Type wheel structure for impact printers



United States Patent inventor Walter J. Zenner 1776 Sherwood Road, DesPlaines, Illinois 60016 Applv No. 683,993

Filed Nov. 17, 1967 Patented Oct. 20, 1970 TYPE WHEEL STRUCTURE FORIMPACT PRINTERS 7 Claims, 6 Drawing Figs.

U.S.Cl 101/109, 197/49 Int. Cl B4lj 1/60, B41j 1/32 Field of Search29/159;

[56] References Cited UNITED STATES PATENTS 1,572,233 2/1926 Chamberlin101/110 2,589,682 3/1952 Dudis 101/109 2,757,775 8/1956 Hickerson...197/49 3,168,182 2/1965 Bernard et al. 197/55 3,269,306 8/1966 Smilgys101/110 3,432,018 3/1969 Watanabe eta]. 197/55X Primaryl;'xaminerWilllam B. Penn Allurneyl(inzer, Dorn and Zickert ABSTRACT: Atype wheel for an impact printer comprising a unitary sheet metal typefont bearing embossed type characters arranged in rows and columns, witheach column on a separate angularly disposed face portion of the sheetmetal type font, which affords a shell of regular polygonalcross-sectional configuration. The shell is braced by a series ofpolygonal reinforcing members affixed to its inner surface and isreleasably mounted upon a shaft that projects through axial apertures inthe reinforcing members.

4-2 use I [I], ll I r Patented Oct. 20, 1970 Inventor in mg w TYPE WHEELSTRUCTURE FOR IMPACT PRINTERS This invention relates to type wheels andmore particularly to a light weight type wheel and to a method ofmanufacturing it.

In the typewriter and printing industry, clean, clear and easily legibleprinting has been achieved with type bar machines using hardened steeltype pallets made by a hot forging process. Since, in machines of thatkind, only one type pallet or type bar is moved in printing a character,the weight of the type carrying member is not important. These machines,on the other hand, have other disadvantages which designers haveendeavored to overcome by the use of type wheels.

The type wheel machines have the entire type font carried on a singleunitary member which must be moved to effect the printing of a singlecharacter. When conventional forged steel type is used in a type wheel,the wheel is, of necessity, quite heavy and the speed of themachine isseverely limited. This weight difficulty has been overcome by moldingthe character printing portion of the type wheel from moldable syntheticresins or plastics. However, while such materials are readily fabricatedand provide a light weight type wheel, the type wheels made in thismanner are subject to chipping and wear and the copy produced isgenerally not satisfactory. These molded type wheels have been improvedby electroplating a metallic layer on the molded member and, while thisimproves the wearing quality and the printed copy, the cost of the typewheel is increased without producing copy as good as that produced byforged type pallets.

Accordingly, it is an object of the present invention to provide a typewheel lighter in weight than a molded type wheel and having theadvantages of forged steel type.

Another object of the invention is to provide a type wheel assemblagewhich may be easily mounted and adjusted on its actuating member.

A further object of the invention is the provision of a simple method ofmanufacturing a light weight type wheel.

In accordance with the preferred embodiment of the invention, a typewheel is provided which comprises a substantially tubular, thin walled,structure having a plurality of flat surfaces, angularly disposed withrespect to one another in a polygonal arrangement. Each of the surfacespreferably has a plurality of character printing type extendingoutwardly from it for driving a print ribbon against a sheet to beprinted. Rigidity is imparted to the tubular structure by a plurality ofreinforcing members in the form of disks each having a central apertureand an outer polygonal contour which conforms to the interior of thetubular structure. One such disk is provided for each level of type andeach disk is spot welded to the tubular structure.

In the preferred embodiment of the invention the tubular structure isadjustably mounted on a mounting and positioning member, a spring clipbeing seated in a circumferential notch in a mounting and positioningmember to compress a spring washer against the outermost reinforcingdisk and to force the innermost disk against a spacer ring. A mountingand positioning member has a collar fixed to it which has a plurality ofequally spaced apertures in it for receiving a spacer pin that is fixedin the spacer ring and may be entered into any one of a plurality ofequally spaced apertures in the innermost disk. The spacing of theapertures in the innermost disk and in the spacer ring are very slightlydifferent whereby minute adjustment of the tubular type wheel structurewith respect to a mounting and positioning member, may be effected.

Preferably, the embossment of the type and the forming of the tubularstructure are effected simultaneously by feeding a sheet of steel into apunch and die having cooperating surfaces comprising projecting typecharacter-forming and strip-bending portions on the punch and typecharacter-forming and strip-bending recesses in the die. The cooperatingtype character forming portions stress the strip of steel beyond itselastic limit to emboss the type in transverse rows on the strip and thebending portions stress the strip beyond its elastic limit in transverselines between the rows of type characters.

A more complete understanding of the invention may be had by referenceto the following detailed description when considered in conjunctionwith the accompanying drawing wherein:

FIG. 1 is a fragmentary view of a printer showing the type wheel in acooperative relation to a wheel driver and a paper supporting platen;

FIG. 2 is a transverse sectional view taken substantially along the line22 of FIG. I, in the direction of the arrows and showing, on an enlargedscale, the end of the mounting and positioning member, the spring clipand spring washer in plan;

FIG. 3 is a sectional view taken substantially on the line 3-3 of FIG. 2in the direction of the arrows showing details of the adjustablemounting features;

FIG. 4 is a view looking in the direction of the arrows on line 4-4 ofFIG. 3, parts being broken away to illustrate the adjustable mounting ofthe wheel on its mounting and positioning member;

FIG. 5 is a diagrammatic sectional view of a punch press illustratingthe method of making the tubular type bearing structure; and

FIG. 6 is an enlarged, broken, developed view of the strip of sheetmetal with the type embossed on it.

Referring to the drawings and particularly to FIG. 1, it will be seenthat a type wheel of the class disclosed herein may be used in atelegraph printer of the type disclosed in the US. Pat. No. 3.176.069.issued Mar. 30, I965 to W. J. Zenner. As illustrated in that patent, ashaft supports a type wheel 186 for reciprocation and rotation to selecta character for printing and for oscillation to effect printing. Thetype wheel 186 moves across a platen 271 and an inking ribbon 272 andthe type wheel 186 is driven to engage the ribbon 272, for effectingprinting, by a print hammer 293. In the present invention the type wheel186 is of distinctly different construction and is mounted in a novelmanner on the mounting and positioning member for the type wheel, theshaft 190.

In the embodiment of the invention disclosed herein. the portion of thetype wheel 186 on which the character printing type are formed is aneight-sided substantially tubular sheet metal member 10 which could haveany desired number of sides depending on the number of charactersrequired for printing of a text. This eight-sided member 10 is formedfrom a single sheet of metal in the manner illustrated in FIG. 5,wherein there is shown a punch 11 having a suitable shank 12 forattaching it to the head of a punch press (not shown).

The entire sheet metal member 10 is formed in one stroke of the press byshearing the body of the member 10 from a sheet 13 of metal stockleaving scrap as indicated at I4 and 15. In this shearing operation, thepunch 11 forces the member 10 into a cavity 16 in a die block 17,cutting the member 10 from the sheet 13 and forming a registering notch18 and tab 19 (FIG. 6). Continued movement of the punch 11 into the dieblock 17 forces printing character forming projections 20 into themember 10 and forms the metal of the member 10 into recesses 21 in thedie block 17. In this type forming operation the sheet metal is deformedbeyond its elastic limit and consequently sharp, clear, characterdelineating ridges 22 are embossed on the sheet metal member 10.

Simultaneously with the forming of the character delineating ridges 22,the member 10 is stressed, along lines 23 transverse to its length,beyond its elastic limit. This is effected by providing sharp ridges 24on the punch 11 in alignment with the sharply angled surfaces of the dieblock at the lines 23. The mating surfaces of the punch 11 and die block17 are gently curved from the lines 23, to bend the member 10 within itselastic limit in the area marked 25, (FIG. 5), to afford a flat orrelatively flat area 26 adjacent each of the printing characterprojections 20 and recesses 21.

When the punch 11 is retracted from the die block 17 the member 10,having been embossed with all of the character delineating ridges ortype faces 22 of the type font and also having been bent beyond itselastic limit along the lines 23, will assume a configuration as shownin section in FIG. 2.

Thus, the member with the type faces or ridges 22 extending from itsouter surfaces forms, in this case, the outer shell of an octagonalflat-sided substantially tubular printing member. The member 10 willhave eight rows of type on its outer surface, in four levels, asillustrated in FIG. 6, which levels will be aligned by nesting the tab19 in the notch 18.

In order to impart rigidity to the member 10 and to supply means formounting the member on the shaft 190, four octagonally shapedreinforcing members 30 are attached to the inner surface of the member10 by spot welds 31. As shown in FIG. 3, the reinforcing members 30 arefixed to the member 10 at approximately the vertical centers of the typecharacter printing elements 22 by applying the spot welds at the cornersformed along the lines 23. All of the reinforcing members 30 areprovided with central apertures 32 of a diameter to snugly fit on theshaft 190 and at least the bottom member 30 is provided with a pluralityof locating holes 33 which are evenly spaced one from the other in acircle and disposed in the area between the central aperture 32 and theperiphery of the member 30.

The shaft 190 has a shouldered collar 34 fixed to it by means of a pin35. This collar is provided with a plurality of locating holes 36 whichare arranged in the same manner as the locating holes 33 in thereinforcing member 30, except that, while the holes 36 are arranged withtheir axes the same distance from the axis of the actuating member 190as the holes 33 and are equally spaced one from the other, the spacingbetween the holes 36 is slightly smaller than the spacing between theholes 33. The locating holes 33 and 36 are of the same size, chosen tosnugly fit with a locating pin 37 which is fixed in a locating ring 38that encircles and is free to move on the actuating member 190. Thelocating pin 37 extends beyond the upper and lower surfaces of thelocating ring 38 and may be selectively positioned in the holes 33 and36 in the reinforcing member 30 and collar 34 to provide a very fineadjustment of the type wheel 186 with respect to the shaft 190.

Near its upper end, the shaft 190 has an annular recess 39 formed in itfor receiving the projecting arms 40 of a hairpin type fastener 41, theclosed end of which is bent upwardly as shown at 42. The fastener 41 iswedged between the upper surface of the recess 39 and an annular springwasher 43 which encircles the actuating member and presses the typewheel structure 186, comprising the member 10 and its reinforcingmembers 30, firmly onto the collar 34.

Although a specific embodiment of the invention has been shown in thedrawings and described in the foregoing specification, it will beunderstood that the invention is not limited to the specific embodimentbut is capable of modification, substitution and rearrangement withoutdeparting from the spirit of the invention.

1 claim:

1. A type wheel assemblage for a step-by-step impact printer comprising:

a unitary sheet metal type font member deformed along a series ofparallel transverse lines to form a plurality of contiguous, angularlydisposed face portions, each face portion having at least one typecharacter printing element embossed therein and projecting outwardly ofits outer surface, the angular relation of the face portions, one to theother, being such that said face portions form a substantially tubularsheet metal shell having a cross-sectional configuration conforming to aregular polygon;

a plurality of polygonally shaped reinforcing members, each having aperiphery which conforms in size and configuration to the interior ofsaid shell, affixed to the inner surface of said shell in alignment withthe midportions of the type elements to afford a substantially tubulartype font structure with the type elements arranged in rows and columnsthereon, said reinforcing members each having an axial aperture forreceiving a mounting and positioning member;

a mounting and positioning member projecting through said axialapertures in said reinforcing members; and

means for attaching the reinforcing members to the mounting andpositioning member to mount said type font structure thereon.

2. The type wheel assemblage defined in claim 1 wherein the sheet metalmember is formed from a single sheet of metal having a notch at one edgeand a complementary tab at the opposite edge and is prestressed alongsaid transverse lines at the edges of the face portions to engage thetab at said opposite end in the notch at said one end.

3. The type wheel assemblage as defined in claim 1 wherein the mountingand positioning member is a shaft, and in which the attaching meansincludes an annular collar fixed to the shaft, a locating ring restingon said collar, and means for compressing one of the endmost reinforcingmembers fixed to the sheet metal member against said ring on the collar.

4. The type wheel assemblage as defined in claim 3 wherein thecompressing means includes a fastener member engaged with a surface ofthe shaft and'a resilient member compressed between the fastener memberand the other endmost one of the reinforcing members.

5. The type wheel assemblage as defined in claim 3 wherein the annularcollar and said one endmost reinforcing member each include internallocating surfaces, and wherein the locating ring has a locating memberfixed to it for registration with said locating surfaces in both theannular collar and said one endmost reinforcing member.

6. The type wheel assemblage as defined in claim 5 wherein the locatingsurfaces in the annular collar and in the one endmost reinforcing memberare the edge surfaces of holes that are arranged in circles equallyspaced from the axis of the shaft, the holes in the collar are equallyspaced, one from the other, by a predetermined distance, the holes inthe said one endmost reinforcing member are equally spaced, one from theother, a distance slightly different from the spacing of the holes inthe collar and the locating member is a pin fixed in the locating ringin position for selective registration with the holes in the collar andsaid one endmost reinforcing member whereby minute rotative adjustmentof the printing structure with respect to its shaft may be achieved.

7. The type wheel assemblage as defined in claim 2 wherein thereinforcing members are fixed to the sheet metal member by spot welds atthe interior junctures of the face portions.

